The present invention relates to discharge chute assemblies and, in particular, telescopic discharge chute assemblies for concrete mixer trucks.
In many industrial, agricultural and construction operations it is desired to deposit various materials stored or contained in a discharge apparatus to preselected deposit points radially surrounding the discharge apparatus. An example of one such operation includes depositing concrete mix from a concrete mixer vehicle with a chute assembly mounted at a discharge or mixer opening.
Commonly, these concrete mixer vehicles include a main chute section of the discharge chute assembly that is mounted permanently and pivotally to the mixer vehicle. The main chute is mounted with its upper end beneath the mixer discharge opening and its lower end supported by an extendible hydraulic piston and cylinder mechanism that permits selective angles of inclination of the discharge chute assembly. A second chute section is pivotally connected to the lower end of the main chute section thereby allowing the second chute section to fold from an operational position where the second chute acts as an extension of the main chute to a storage position folded on top of the main chute section. Additional chute sections can be attached in series to a lower end of the second chute section to provide a chute assembly having desired length. These additional chute sections usually are detachable and are stored on a portion of the vehicle frame, and normally have hook means on each section for interconnecting these sections to form the complete discharge chute assembly. Although such detachable chute assemblies allow the discharge of concrete mix to preselected deposit points, the requirement of manually connecting and disconnecting detachable chute sections is a time consuming exercise.
Other known discharge chute assemblies incorporate permanently connected telescoping chute sections rather than using additional detachable chute sections. Two known telescoping chute assemblies are disclosed in U.S. Pat. No. 3,157,262 to Chapdelelaine and U.S. Pat. No. 4,711,334 to Barry et al. U.S. Pat. No. 3,157,262 discloses a telescopic chute assembly that has chute sections that retract into a main chute section located beneath the mixer opening. U.S. Pat. No. 4,711,334 teaches a telescoping chute assembly with the telescoping sections forming a compact assembly that is hinged for storage above a main chute section. While both telescopic chute assemblies described above reduce the time needed to set up and deliver concrete mix to a particular site, permanent connection of each chute section prevents convenient operation when a shorter, less bulky chute assembly is needed. The extension of the chutes also is difficult in its pin devices.
Finally, it is often desirable to locate the discharge chute assembly, in particular an inlet end of a main chute section, at an elevation as high as possible to allow for longer extension of the chute assembly. However, constraints such as the requirement that the chute assembly and discharge vehicle have a low enough profile to pass under bridges must be considered.
Thus, there is a continuing need for improved extendable chute assemblies to be used with discharge apparatus such as concrete mixer vehicles and which have an adjustable overall height.